Apparatus for providing regulated power to an integrated circuit

ABSTRACT

A regulator system for supplying power to a microelectronic device is disclosed. The system includes an array of a plurality of regulators, where each regulator provides a portion of power required to operate the device. The system may further include an intermediate power regulator that supplies power to the array of regulators.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to United States ProvisionalApplication Serial No. 60/178,421, filed Jan. 27, 2000, entitled“Apparatus for Regulating Power to an Integrated Circuit.”

TECHNICAL FIELD

[0002] The present invention generally relates to microelectronicdevices. More particularly, the present invention relates tomicroelectronic devices suitable for regulating power.

BACKGROUND OF THE INVENTION

[0003] Regulators are often employed to provide a desired, regulatedpower to microelectronic devices such as microprocessors. For example,switching regulators such as buck regulators are often used to step downa voltage (e.g., from about 3.3 volts) and provide suitable power to amicroprocessor (e.g., about 10-30 amps and about 2-3 volts).

[0004] To increase speed and reduce costs associated withmicroprocessors, microprocessor gate counts and integration generallyincrease, while the size of the microprocessor per gate generallydecreases. As gate counts, speed, and integration of microprocessorsincrease, supplying requisite power to microprocessors becomesincreasingly problematic. For example, a current required to drive theprocessors generally increases as the number of processor gatesincreases. Moreover, as the gate count increases per surface area of aprocessor, the operating voltage of the processor must typicallydecrease to, among other reasons, reduce overall power consumption ofthe processor. Furthermore, as the microprocessor speed increases, themicroprocessors demand the higher current at faster speeds.

[0005] Although buck regulators are generally suitable for controllingpower to some microprocessors, such regulators are not well suited tosupply relatively high current (e.g., greater than about 30 amps) atrelatively high speed (e.g., greater than about 500 MHz.). One reasonthat buck regulators have difficulty supplying high current at highspeed to the microprocessor is that the current supplied from theregulator to the processor has to travel a conductive path thatgenerally includes a portion of a printed circuit board that couples theprocessor to the regulator. The relatively long conductive path betweenthe processor and the regulator slows a speed at which the regulator isable to supply current to the processor. In addition, as microprocessorspeed and current demands increase, the buck controller simply cannotprovide the desired amount of current at the desired rate.

[0006] Yet another problem with buck regulators is that they aregenerally configured to supply power to within about ±5% of a desiredvalue. While this range may be acceptable for processors running atrelatively low currents, this range becomes decreasingly acceptable asthe current requirements of microprocessors increase. Thus, asmicroprocessor gate counts and clock speeds increase, improved methodsand apparatus for supplying high current at high speed and low voltageare desired. Furthermore, methods and apparatus for supplying therelatively high current within a relatively tight tolerance is desired.

SUMMARY OF THE INVENTION

[0007] The present invention provides improved apparatus and techniquesfor providing regulated power to a microelectronic device. Moreparticularly, the invention provides improved devices and methodssuitable for supplying electronic devices with relatively high,regulated current at relatively high speed.

[0008] The way in which the present invention addresses the deficienciesof now-known regulators and power supply systems is discussed in greaterdetail below. However, in general, the present invention provides anarray of power regulators that provides power to a singlemicroelectronic device.

[0009] In accordance with one exemplary embodiment of the presentinvention, an array of regulators is configured to provide power to amicroprocessor. In accordance with one aspect of this embodiment, thearray is formed as an integrated circuit on a semiconductor substrate.In accordance with a further aspect of this embodiment, the circuit iscoupled to the microprocessor through a relatively short conductive path(e.g., by coupling the circuit to the device via bump interconnects). Inaccordance with yet a further aspect of this embodiment, the arraycircuit is formed on a silicon germanium (SiGe) substrate to facilitatefaster current supply to the device. In accordance with a furtherexemplary embodiment of the present invention, a tiered power regulationsystem is configured to provide power to a microelectronic device. Thetiered system includes at least two levels of power regulation. Inaccordance with an exemplary aspect of this embodiment, a first level ofpower regulation includes a switching regulator and a second level ofregulation includes a linear regulator. In accordance with a furtheraspect of this embodiment, the second level of regulation includes anarray of linear regulators.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 illustrates a power regulation system in accordance with anexemplary embodiment of the present invention;

[0011]FIG. 2 illustrates a power regulation system in accordance withalternative embodiment of the present invention; and

[0012]FIG. 3 schematically illustrates a portion of a regulator array inaccordance with an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0013] The present invention generally relates to microelectronic powerregulators. More particularly, the invention relates to regulatorssuitable for providing high current, high speed power to microelectronicdevices and to electronic systems including the regulators. Although thepresent invention may be used to provide power to a variety ofmicroelectronic devices, the invention is conveniently described belowin connection with providing power to microprocessors.

[0014] An exemplary power supply system 100 in accordance with thepresent invention is schematically illustrated in FIG. 1. Asillustrated, system 100 includes an intermediate regulator 110, aregulator array 120, including regulators 120(a)-120(n), and amicroprocessor 130. System 100 may also suitably include a powerconverter 140 and one or more discrete electronic components,collectively represented as components 150.

[0015] In general, system 100 is configured to provide relatively highcurrent (e.g., 30 to more than 100 amps) at relatively low voltage(e.g., down to about 1 volt or less) with a relatively short responsetime. As discussed in greater detail below, in accordance with thepresent invention, system 100 provides the high current power tomicroprocessor 130 by distributing the power regulating duty to aplurality of regulators (e.g. regulator 110 and/or regulators120(a)-120(n)).

[0016] Converter 140 of system 100 is generally configured to convertalternating current (AC) power obtained from a typical AC power outletto direct current (DC) power to, for example, provide suitable DC powerfor a motherboard of a computer. For example, in accordance with oneexemplary embodiment of the present invention, converter 140 isconfigured to convert 110 volt AC power to about 3.3 volts to about 15volts DC power at about 1 amp to about 20 amps. In accordance with oneaspect of this embodiment, converter 140 includes multiple DC poweroutputs—e.g., about 12 volts at about 1 amp, about 5 volts at about 5amps, at about 3.3 volts at about 30 amps to supply the power to, forexample, various types of microelectronic devices which may be coupledto the motherboard. In accordance with alternative embodiments of thepresent invention, converter 140 may include any number of DC poweroutputs, and the amount of power associated with each output may vary inaccordance with a type of device coupled to the output of converter 140.

[0017] Intermediate regulator 110 is a DC-to-DC converter, which isdesigned to convert output from converter 140 to higher current, lowervoltage power. In accordance with one exemplary embodiment of thepresent invention, regulator 110 receives power (e.g. 3.3 volts at 30amps) from converter 140 and converts the power to about 1.15 volts atabout 100 amps. Regulator 110 may be a linear regulator, a switchingregulator, or any other suitable type of power controller; however, inaccordance with one exemplary embodiment of the present invention,regulator 110 comprises a switching regulator such as a buck regulator.

[0018] System 100 may also optionally include discrete components 150 tofacilitate rapid response power transfer from regulator 110 to array120. In particular, components 150 may include capacitors to store anappropriate charge and discharge the energy as array 120 calls for powerfrom regulator 110.

[0019] Regulator 120 is generally configured to provide high current(e.g., up to 100 amps or more) power at a relatively low response time(e.g., at speeds of 500 MHz and above) to microprocessor 130. Inaccordance with an exemplary embodiment of the present invention, array120 includes one or more power regulators (e.g., regulators120(a)-120(n)) configured to transform power received from regulator 110and/or components 150 and convert the power into higher current, lowervoltage power suitable for microprocessor 130.

[0020] Array 120 may include any number of regulators, which may beconfigured and coupled to processor 130 in a variety of ways. Forexample, array 120 may include a number (n) of substantially identicalregulators, wherein each regulator is configured to provide processor130 with 1/n the operation power of processor 130. However, inaccordance with alternate embodiments of the invention, array 120 may beconfigured with regulators of various sizes that are configured toprovide power to various portions of processor 130. For example, array120 may include relatively high current regulators to provide power toinput/output buffers and relatively low current regulators to supplypower to logic units of the microprocessor.

[0021]FIG. 2 illustrates a power supply system 200 in accordance with analternative embodiment of the invention. Similar to system 100, system200 generally includes an intermediate regulator 210, a regulator array220, including regulators 220(a)-220(n), a microprocessor 230, andoptionally a power converter 240 and components 250.

[0022] System 200 is configured such that a portion of power supplied tomicroprocessor 230 may be derived from regulator 210. For example, inaccordance with one aspect of this embodiment, regulator 210 suppliespower to input/output contacts of microprocessor 230 and/or a floatingpoint contact of microprocessor 230. However, the invention is not solimited; system 200 may suitably be configured such that regulator 110provides power to any portion of microprocessor 230.

[0023]FIG. 3 is a schematic illustration of an array 300, showingregulators 310, 320, 330, and 340 coupled to a common voltage reference350 in accordance with an exemplary embodiment of the present invention.In accordance with the embodiment illustrated in FIG. 3, each regulator310-340 is configured to supply substantially the same power (at thereference voltage) to a microprocessor—e.g., microprocessor 130.

[0024] Regulators 310-340 may include switching regulators, linearregulators, combinations thereof, or other suitable devices forcontrolling power. In accordance with one exemplary embodiment of thepresent invention, regulators 310-340 are linear regulators and eachregulator 310-340 suitably includes a transistor (e.g., bipolartransistors 312, 322, 332, and 342), an error amplifier (e.g., erroramplifier 314, 324, 334, and 344), and a voltage source (e.g., sources316, 326, 336, and 346).

[0025] As noted above, regulators 310-340 are generally configured toprovide output power to processor 130 at a voltage substantiallyequivalent to voltage reference 350. However, regulators 310-340 maysuitably be trimmed such that the output voltage can be set to about ±1%of the reference voltage. In accordance with alternative embodiments ofthe present invention, array 300 may include multiple voltage referencesat various voltages, with one or more regulators tied to each reference.Use of multiple voltage references allows for power regulation at thevarious voltage levels to various portions of microprocessor 130.

[0026] In accordance with one exemplary embodiment of the invention, allregulators (e.g., regulators 310, 320, 330, and 340) are suitablycoupled together in parallel such that, in addition to each regulatorbeing tied to a common reference voltage, each regulator array 300 istied to a common collector structure. The parallel coupling ofregulators within an array allows for a total current output of array300 which is equal to the sum of current outputs from each regulatorwithin array 300. Thus, time delays associated with larger regulatorsare mitigated because smaller regulators within an array are used toprovide current to a portion or portions of microprocessor 130. In otherwords, microprocessor 130 does not depend on a single, large regulatorto supply requisite current.

[0027] A conductive path between array 120 and microprocessor 130, or aportion thereof, is preferably relatively short to reduce the effects ofparasitic inductance between an array (e.g. array 120) andmicroprocessor 130. Providing a relatively short conductive path betweenarray 120 and microprocessor 130 is additionally advantageous becauseparasitic inductance between array 120 and processor 130 is generallyreduced as the distance between the components is reduced. One techniquefor providing a relatively short conductive path between array 120 andmicroprocessor 130 in accordance with the present invention is to couplearray 120 to processor 130 using conductive bumps such as C4 (ControlledCollapse Chip Connection) bumps. In accordance with various aspects ofthis embodiment, array 120 may be coupled directly to microprocessor130, or array 120 may suitably be coupled to a package containingmicroprocessor 130.

[0028] To facilitate fast power delivery from regulators 120(a)-120(n)of array 120 to processor 130, regulators 120(a)-120(n) are formed on asemiconductor substrate having relatively high electron mobility such assilicon germanium (SiGe), Gallium Arsenide (GaAs), or the like. Formingregulators on SiGe or similar substrates that have relatively highelectron mobility allows relatively quick power transfer (e.g., on theorder of GHz speed) between regulator 120 and microprocessor 130. Inaddition, semiconductive substrates such as SiGe exhibit a relativelyhigh current density, compared to conventional semiconductor materials,which allows for formation of more transistors per surface area of SiGecompared to substrates having lower current density such as silicon.

[0029] In accordance with an alternative embodiment of the presentinvention, a regulator array and microprocessor 130 are formed on asingle semiconductive substrate formed of, for example, SiGe, or othersuitable semiconductive materials. Integrating an array and amicroprocessor on a single substrate allows for even faster power supplyfrom the array to the microprocessor. The integral array may providepower to all or a portion of the microprocessor and may be in additionto or in lieu of an array, such as array 120 illustrated in FIG. 1.

[0030] Although the present invention is set forth herein in the contextof the appended drawing figures, it should be appreciated that theinvention is not limited to the specific form shown. For example, whilethe invention is conveniently described above in connection withproviding power to a discrete microprocessor, the present invention maysuitably be used provide power to a plurality of microelectronicdevices. Various other modifications, variations, and enhancements inthe design and arrangement of the method and apparatus set forth hereinmay be made without departing from the spirit and scope of the presentinvention as set forth in the appended claims.

We claim:
 1. A microelectronic power supply system comprising an arrayof power regulators coupled together, wherein each regulator in thearray is configured to provide power to a portion of a microelectronicdevice.
 2. The microelectronic power supply system of claim 1, furthercomprising an intermediate regulator coupled to said array.
 3. Themicroelectronic power supply system of claim 2, wherein saidintermediate regulator is a switching power regulator.
 4. Themicroelectronic power supply system of claim 3, wherein saidintermediate regulator provides power to a microelectronic device and tosaid array of power regulators.
 5. The microelectronic power supplysystem of claim 1, further comprising a power converter.
 6. Themicroelectronic power supply system of claim 1, further comprisingelectronic components coupled to said array of power regulators.
 7. Themicroelectronic power supply system of claim 6, wherein said electroniccomponents include capacitors.
 8. The microelectronic power supplysystem of claim 1, wherein said array is formed using SiGe.
 9. Themicroelectronic power supply system of claim 1, wherein said powerregulators of said array comprise linear regulators.
 10. Themicroelectronic power supply system of claim 1, wherein at least one ofsaid regulators of said array comprises a transistor and an erroramplifier.
 11. The microelectronic power supply system of claim 1,wherein a plurality of said regulators of said array are coupledtogether in parallel.
 12. The microelectronic power supply system ofclaim 1, wherein a plurality of collector regions of said regulators ofsaid array are coupled together.
 13. The microelectronic power supplysystem of claim 1, wherein said array comprises conductive bumps.
 14. Amicroelectronic regulator array comprising a plurality of regulatorscoupled together in parallel, said array configured to provide about 110amps at more than about 500 MHz.
 15. The microelectronic regulator arrayof claim 14, wherein at least a portion of collector regions of saidregulators are coupled together.
 16. A tiered power regulation systemcomprising: an intermediate power regulator; and a regulator arraycomprising a plurality of power regulators, wherein at least a portionof the plurality of power regulators are coupled to a common voltagesource.
 17. The tiered power regulation system of claim 16, wherein saidintermediate power regulator is a switching regulator.
 18. The tieredpower system of claim 16, wherein at least one of said plurality ofregulators is a linear power regulator.